That's not even universally true, though. I've been to bars where they scan the barcode on my drivers' license. I assume that's more convenient than reading the data off it, so maybe they're just doing it for convenience and aren't storing the data anywhere, but who knows, maybe they are. Maybe there's a database somewhere with a list of name, date, time, location tuples for some of my bar visits from years ago. Creepy.
Not well-designed ones. I think you overestimate how much retailers want to even possess sensitive information like that.
What's going to be stored is the fact that an of-age ID was scanned, and possibly the DOB. This is to protect honest cashiers and to have a way to punish ones who might sell to the underage. If an underage sale is reported, they check the audit log and it says the transaction had an ID scanned the cashier can be cleared of wrongdoing. Unless it's the same DOB always being scanned, which seems like some kind of dishonesty.
I do not buy that the supermarket chain wants to use your ID card data for any purpose. First of all, they don't need to, they have (most people's) loyalty cards that do a much better job as they're swiped or entered even without buying any beer. Second, again, only downsides come from saving it. If they were to sell the data and be caught, terrible. If they were to get hacked, terrible.
Your comment made sense perhaps only twenty years ago. But today, everyone is desperate for this kind of info. Third-parties provide these services for free or close to it, especially to get access to the data stream.
Someone was on here a couple of years ago stating that even "line item" level data on your receipt is now being transmitted in a lot of cases, and growing.
The bottom line today—never expect a company to default to respect of your privacy. Simply too lucrative.
You're talking about something else there though: Data about what is bought and the demographics who buy it. They collect that data with loyalty cards, and the ones who don't use loyalty cards may collect that by some effective hash of a credit card number.
The store isn't tying your drivers license number and specific DOB to your purchases because you show an ID to buy beer -- that's a different kind of data and carries with it way too much potential for identity theft. Thinking that they want that is tinfoil-hat thinking. You can ask every single supermarket company if they do that and every one will tell you no. You can ask the companies which make the POS software if the scan ID functionality ties into data brokers and they'll say no. But go ahead and think that there are like 15 Fortune 500 companies all secretly doing this, even though not a single whistleblower has ever come forward. Of every engineer at those companies, I am not aware of anyone who has alleged this from a position of actual knowledge.
